This invention relates to card readers for cedit-card type electronic memory cards. Such readers have a card introduction and guide slot into which a card is inserted. The memories for such cards generally include the memory proper and associated memory read and write control circuits, decoding and addressing circuits, all of which are implanted in the card. The circuit terminals are connected to contact pads on the card surface. The reader has electrical contact elements for contacting the card contact pads. Electrical power and signals are supplied through the contact elements and pads to the integrated circuit.
As the card is inserted into the slot the card reader contact elements and the card contact pads progressively overlap. Whatever precautions are taken in fabrication so that the reader contact elements present the same spatial configuration as the card contact pads, the contact pad length along the axis of card movement sometimes permits contact connections to be established out of order. Electrical power supply or information transfer signals applied to the integrated circuit of the card in the wrong order can deteriorate or cause a malfunction in the card.